Spacer deck for engine cylinder block



Aug. 13, 1968 c. N. FANGMAN ET AL I 3,396,711

SPACER DECK FOR ENGINE CYLINDER BLOCK Filed June 20, 1967 \rao CHARLES N. FANGMAN WALTER R.GUTZW|LLER CLAYTON c. JOHNSON BY Wfi Mw. W

' ATTORNEYS INVENTORS United States Patent 3,396,711 SPACER DECK FOR ENGINE CYLINDER BLOCK Charles N. Fangman, Walter R. Gutzwiller, and Clayton C. Johnson, Peoria, Ill., assignors to Caterpillar Tractor Co., Peoria, Ill., a corporation of California Filed June 20, 1967, Ser. No. 647,492 1 Claim. (Cl. 123-193) ABSTRACT OF DISCLOSURE The spacer deck of the invention is formed of a plate securable to the top surface of an engine cylinder block. Extending through the plate are a plurality of circular apertures, positioned respectively for registration with the cylinder bores. Each aperture is of larger diameter than the corresponding bore. Associated with the deck is a sheet of sealing material securable intermediate the deck and the top surface of the block. A portion of the sheet is positionable adjacent each bore for Seating a support flange of a cylinder liner projecting within the respective bore. Stresses produced in each cylinder liner are transmitted through the associated support flange and sheet portion, and to the top surface of the cylinder block.

Engine cylinder blocks, such as are well known in the prior art, are usually constructed of a cast metal, such as cast iron. Such blocks are ordinarily provided with a plurality of cylinder bores, and a cylinder liner suspended within each bore. Each of the bores is usually formed with a counterbore, which provides a ledge for seating a support flange of the associated cylinder liner. The cylinder block and liner are in most instances so designed, that a small portion of the liner flange projects above the counterbore of the block. Such projection serves to support the cylinder head. The cylinder head gasket is compressed between the clyinder head and the main body portion or the flange.

Because of machining tolerances, the respective depths of the counterbores for any given cylinder block may vary, one from the other. In the case of a counterbore which is comparatively shallow, the corresponding liner projection will be comparatively high. Consequently, when a cylinder head is torqued to the block, unusually high tensile stresses will be created at the stress riser; i.e., at the corner of the counterbore where cracks are most likely to occur. Such stresses may approach the ultimate strength of the material of which the block is constructed.

During operation of the engine, the pressures in each cylinder will increase the stresses in the respective counterbore, and will often initiate cracking of the ledge. Once cracking has begun, it may be further propagated by the cycle gas-firing pressures in the cylinder. As the ledgecracking continues, the level of the liner projection will be lowered, and the degree of compression of the cylinder head gasket consequently increased. Such unusual compression of the cylinder head gasket may cause failure of the latter, with resultant leakage of both fuel and coolant liquid. Such leakage may, in turn, produce failure of the cylinder head.

In accordance with the present invention, there is provided a spacer deck for a cylinder block, the use of which deck serves to overcome the problem of ledge cracking, such as has been discussed hereinabove.

The spacer deck of the invention is in the form of a plate which is seated on the top surface of the cylinder block. The plate is provided with an aperture which registers with each cylinder bore, but which is of larger diameter than the latter. A portion of the top surface, surrounding each cylinder, is thus left exposed. Each of the exposed surface portions provides a seat for a support "Ice flange of a cylinder liner projecting within the respective bore.

Support of the cylinder liner at the top surface of the cylinder block serves to avoid the danger of ledge cracking. At the same time, uniform compression of the cylinder head gasket is attained. As a consequence, a major cause of cylinder head failure is avoided, and the life of the cylinder block-cylinder head assembly is greatly increased.

Other advantages of the present invention will become apparent to one skilled in the art, from the following description, when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a vertical cross-sectional view of an engine cylinder block and cylinder head assembly, incorporating the present invention;

FIG. 2 is an enlarged vertical cross-sectional view of part of the assembly of FIG. 1; and

FIG. 3 is a perspective view, being partly broken away, of the spacer deck of the invention, shown together with a sheet of sealing material.

In FIG. 1, there is shown a cylinder block-cylinder head assembly 10 of a multicylinder internal combustion engine. The assembly 10 includes a cylinder block 12 which is of conventional design, and which presents a comparatively flat top surface 14. Formed in the block 12, and opening at the surface 14, are a plurality of aligned cylinder bores 16 (one being seen).

Positioned on the top surface 14 is a sheet 18, of sealing material (see also FIGS. 2 and 3). The sheet 18 is of the same length and breadth as the top surface 14. The sheet 18 is formed with a plurality of circular apertures 20, each being positioned for registration with one of the bores 16. Each aperture 20 is of the same diameter as the bore 16 with which it registers. The sheet 18 also provides a plurality of apertures 21, of comparatively small diameter.

The sheet 18 is preferably constructed of shim stock. However, the sheet 18 may alternatively be constructed of conventional sealing gasket material.

Seated on the top surface 22 of the sheet 18 is a spacer deck constructed in accordance with the invention. The deck 24 is in the form of a comparatively flat plate of metallic material, such as cast iron or aluminum. The deck 24 is of the same length and breadth as the surface 14 and the sheet 18.

Formed in the deck 24 are a plurality of circular apertures 26. Each of the apertures 26 is positioned for registration with one of the bores 16, and thus also with one of the apertures 20 of the sheet 18. However, each of the apertures 26 is of larger diameter than the bore 16 and aperture 20 with which it registers. The deck 24 consequently leaves exposed a circular portion 27 of the top surface 22 of the sheet 18, surrounding each of the bores 16.

The sheet 18 except for the exposed portions 27, is preferably coated with a sealing material. The sealing material employed may, for example, be a liquid mixture of rubber and a solvent. One type of sealing material which is suitable for the purpose is described in U.S. Patent 3,116,198.

The deck 24 is also formed with a plurality of apertures 28, corresponding in size and positioning to the apertures 21 of the sheet 18. A set of still smaller apertures 29 is additionally provided in the deck 24.

Projecting wiihin each of the bores 16 is a cylinder liner 30. Each of the liners 30 is constructed of a cylindrica-l side wall 32, which defines a combustion chamber 3 4. Spaced a short distance from the upper end 36 of each side wall 32 is a peripherally-extending support flange 38 of the same thickness as the deck 24. Each side 3 wall 32 projects a short distance above the respective flange 38, as seen at 40.

Each of the flanges 38 is seated upon one of the exposed portions 27 of the top surface 22 of the sheet 18. Adjacent its lower end 42, each of the liners 30 is sealed within the respective bore 16 in conventional manner such as seen at 44.

Mounted on the respective upper ends 36 of the cylinder liner walls 32 is a cylinder head 46 of conventional design and containing a conventional precombustion chamber 48. A cylinder head gasket 50 is disposed between the head and the spacer deck 24.

The sheet 18, the deck 24, the cylinder head 46 and the gasket 50 are clamped securely to the cylinder block 12. Studs (not shown), which are of suitable length, are employed for the purpose. Such studs pass through the apertures 21 in the sheet 18, and the apertures 28 in the deck 24. These studs also pass through similar apertures (not shown) in the gasket 50, and in the attachment flanges (not shown) for the cylinder head 46.

Each of the cylinder liners 30 is maintained securely in position by the respective flange 38, supported on the respective portion 27 of the sheet 18; by the cylinder head 46, which bears against the respective projection 40; and by the respective seal 44. The deck 24 serves the purpose of a spacer, as between the sheet 14 and the gasket 50.

The apertures 29 in the deck 24 are employable for the circulation of a cylinder coolant, in conventional manner.

The sheet 18 serves as a seal between the block 12 and the deck 24. If shim stock is employed for the construction of the sheet 18, the latter also serves to prevent fretting of the top surface 14 of the cylinder block 12. Such prevention of fretting results from the fact that the steel material of the shim plate is more durable than cast iron, such as is usually employed for the construction of the block 12.

The deck 24 can be constructed of relatively low strength material, such as cast iron or aluminum. This results from the fact that the deck 24 is employed only for spacing purposes, and is not directly placed under stress.

The use of the deck 24 in the assembly serves the advantage of substantially eliminating the problem of ledge cracking, such as has been prevalent in the prior art. Thus, the stresses on the wall 32 of each cylinder liner 3 0 are transmitted through the respective flange 38 to the sheet 18. From the latter, such stresses are transmitted to the top surface 14 of the cylinder block 12.

The use 'of the deck 24 also serves to provide a more consistent degree of compression throughout the cylinder head gasket than has been obtained in the cylinder head assemblies of prior art. This results from the fact that all of the flanges 38 are supported by a common surface of the cylinder block'12; i.e., the top surface 14.

We claim:

1. A spacer deck for an engine cylinder block 'having a top surface and a plurality of cylinder bores opening at said top surface, said deck comprising a plate adapted for seating on said top surface, said plate being formed with a plurality of circular apertures positioned for registration with said bores, respectively, each aperture being of larger diameter than the respective bore, each aperture being adapted to encircle a cylinder liner supported at said top surface and projecting within the respective bore, a sheet of sealing material sealing said plate to said top surface, said sheet being adapted for positioning intermediate said top surface and said plate, said sheet being formed with a plurality of circular apertures positioned for registration with said bores, respectively, each aperture of said sheet being of the same diameter as the respective lbore, said sheet being adapted to present a seating surface for a support flange of a cylinder liner projecting within each bore, and said sheet being constructed of shim stock.

References Cited UNITED STATES PATENTS 1,306,843 6/1919 Wolgamon 123-41.84 2,710,602 6/1955 Maybach 123--41.82 3,168,081 2/1965 Bauer 123-41.84

FQREIGN PATENTS 391,386 4/1933 Great Britain.

WENDELL E. BURNS, Primary Examiner. 

